1. Field of the Invention
The present invention relates generally to toner cartridges, and in particular, to techniques for reducing toner cartridge leaks.
2. Description of the Related Art
In general, toner cartridges are relatively large, and oftentimes contain a large amount of toner (e.g., 1 kg of toner, or more). With such a large plastic vessel and toner load, the cartridge is prone to large amounts of flexure when exposed to shock loading. This flexure allows the release of toner from the cartridge, which causes a number of problems. For instance, the released toner is messy and may come into contact with end users. In addition, such unintended toner release causes a reduction in the printing life of the cartridge due to toner loss, and in some cases renders the cartridge unusable due to housing and part failure.
In addition to such size and toner load considerations, toner cartridges can be designed to print across the full width of a letter sized page or larger. This requires that an opening be made in the toner cartridge to allow a controlled amount of toner to pass out of the cartridge onto the developer roll. Seals are added around the developer roll to control toner from leaking from the cartridge. However, this large opening creates a relatively long unsupported portion in the cartridge structure (over eight inches or longer in many cases). The deflection of this unsupported portion can be considerable, particularly during high shock loading on the toner cartridge, such as the loading incurred when the cartridge is dropped. For instance, toner cartridges have the potential to be dropped and exposed to large shock forces when being shipped separate from the printer.
In short, dropping or otherwise flexing the toner cartridge can lead to excessive toner leaks, or a damaged cartridge being shipped to the customer. Based on drop test results, attempts have been made to stiffen the developer housing by adding external features.